Multi-speed split-power reduction gear



Aug- 13, 1963 E. A. BRAss 3,100,405

MULTI-SPEED SPLIT-POWER REDUCTION GEAR Filed April 2s, 1962 s sheets-sheet 2 O N o 8 N In t fr e f l l I W u qu (O rg 'o fd' ro l u' O q O l (o (D '9 g 9 l g l i /g c! I 'IIllll/y/A O N O O N o N lo b lo (D fr f' I K l Il I l @y ,L 1Q/ Ar f@ .es o

O O Y' (D Q g I 9 y I 1', E y l O O INVENTOR.

EDWARD A. BRASS.

BY /5 M?? 7" A TORNEYS.

Aug. 13, 1963 E. A. BRASS 3,100,405

MULTI-SPEED SPLIT-POWER REDUCTION GEAR Filed April 23, 1962 s sheets-sheet 's INVENTOR.

EDWARD A. BRASS.

United States Patent() Y 3,100,405 MULTI-SPEED SPLIT-PWER REDUCTION GEAR Edward A. Brass, Norwalk, Conn., assigner to Aveo Corporation, Stratford, Conn., a corporation of Delaware Filed Apr. 23, 1962, Ser. No. 189,638 3 Claims. (Cl. '74764) This invention relates to a multi-speed split-power gear reduction providing a transmission with a plurality of gear ratios suitable for -use in coupling a so-called gas turbine engine with its high rpm. of turbine speeds to power consuming units requiring relatively low rotative speeds, and to provide in such an larrangement for a multiple number of gear lratios in a range normally used.

It is the primary object of the invention to provide a multi-speed gear reduction capable of reducing an input with a relatively high rotative speed to various desired lower rotative speeds.

It is a further object to provide means for shifting from one gear ratio to another without uncoupling the load during such shifting.

It is another object to provide a transmission in whichA a plurality of output rotative speeds Iare provided and wherein planetary carrier rotative speeds are low.

It is a further object to provide transmission in which the engaging and overrunnin-g speeds on the brakes 'and clutches are low.

It is another object to preserve the inherent advantages of the split power type of transmission with regard to eiciency, weight and compactness in a transmission providing for a multiple num-ber of speed ratios.

It is a further object to provide a two-speed forward and one-speed reverse transmission of the type affording large step-down in rotative speed and suitable for use with a gas turbine engine.

It is another object to provide a split-power gear reduction' of varying gear ratio by selectively rendering desired secondary gear sets operable in a split-power combination by provision of braking elements operable to hold certain elements of specific secondary gear sets from rotation, thereby effecting a substitution of gear sets to complete desired spl-it power gear set combinations re-` sulting in a plurality of gear reductions with desired splitpower characteristics and advantages.

The `above and other objects of the invention will appear more fully from the following more detailed description of an illustrative structure and byv reference to the accompanying drawings forming a part hereof and where- FIGURE 1 is a schematic showing of the multi-speed split-power gear reduction in the form of a longitudinal cross section through the several epicyclic gear sets,

vshowing the-split-power :combinations made available by selective actuation of brakes.

FIGURE ,2 is a schematic showing of :a modified form of multi-speed split-power gear reduction :affording two speeds, forward plus reverse, in the form of a longitudinal cross section.

FIGURES 3, 4, and 6 are longitudinal cross sections vwith Vshading to show power ow in the several gear ratios available in the schematic of FIGURE 1.

Specifically, FIGURE 3 shows first gear;

FIGURE 4 shows second gear;

FIGURE 5 shows third gear;

FIGURE 6 -shows fourth gear;

FIGURE 7 is a longitudinal cross section through an illustrative embodiment of a structure employing the schematic showing of FIGURE l.

Referring to the schematic drawing FIGURE 1, reference numeral 10 refers to a gas turbine rotor source of power connected to rotate fan input high speed shaft 12. The two gear set stages 14 (a primary stage) and 16 (a mediate gears 28, a carrier 30, and :a ring gear 32.

ICC

secondary stage) correspond to the basic split power arrangement vshown in copending application Serial No. 69,064, now Patent No. 3,062,073, tiled Novem-ber 14, 1960, and -assigned to the same assignee as this application. The primary gear set stage 14 comprises central gear 18 rotating with the input high speed shaft 12, intermediate gears 20, carrier 22, and ring gear 24. Likewise, the secondary stage 16 comprises a central gear 26, inrltfehre carrier 22 is connected to and rotates with output Vshaft section 34, while the carrier 30 of the secondary stage is a stationary carrier held from rotationby connection to the housing 36, as shown. The primary stage ring gear 24 is connected in positive rotative connection with the secondary stage central gear 26 by the connection 38. The secondary stage ring gear 32 is connected to the output shaft 34 by connection with the carrier 22 through the connections 40, 42 land over-running clutch 44. The primary and secondary stages and connections, above described, comprise the split-power gear set reduction as set forth in the copending application above identified. A power ow through these two stages to the output shaft section 34 provides rst gear of this transmission.

VAdditional gear set stages 46, 48, shown in schematic FIGURE 1, rotate during this rst gear actuation to rotate the output shaft section -50 at the same rotative speed as the shaft section 34, `as Will later appear.

In order `to accomplish a second gear, the first additional gear set stage 46 is provided tto replace the secondary gear set stage 16. This rst additional gear set stage 46y comprises .a central gear 52, intermediate gears 54,

carrier 56, ring gear 58, brake 60, with connector 62.

between carrier 56 and brake mechanism 60. The cenitral gear -26 of the secondary gear l16 is connected to the central gear 52 of the iirst additional gear set stage Y46 by the connector 64. The first additional gear set stage 46 is -put in actuation by fluid pressure, or similar means, of the brake 60, which clauses the normally free carrier 56 to -be held from rotation and thereby supplies a fixed carrier for the first additional gear set stage 46 and this results in the substitution of the gear set stage 46 for the secondary gear set stage 16. The secondary gear set stage 16 freely rotates because of the difference in rotation direction imposed on the ring gear 32l and the fact that the overrunning clutch 44 no longer holds the 'connection of the ring gear 32 to the output shaft. Therefore, the effect of the actuation of the brake 60 is to make a new split-power set comprising the primary gear set stage 14 and the iirst additional gear set stage 46. The split-power flow lin this arrangement is from the carrier 22 of the primary gear set stage`14 to the output shaft section 34 for one portion of the drive and the other portion through the gear set stage 46 from the ring gear 58 through a connector 66 to the output shaft 34 through the funther connecting portion 68, the carrier 70 simply rotating the second additional -gear set stage 48 through the one-way clutch 72 to the output shaft without any speed change through the second additional gear set stage 48. The second additional gear set stage 48 is likewise made up of a central gear 714, intermediate gears 76, ring gear 78. 'I he intermediate gears 76 are carried on the' carrier ,'70, previously mentioned. When it is desired to effect a `third gear speed, the 'brake 80 is actuated. This brake holds the second additional gear vset stage ring gear 78 from rotationandrthereby Ycauses actuation of the second addition-'al gear set stage 4S to effec-t drive through the gear set stage 4S to the second ysection 50 of the output shaft. f

'power path throughgear set stage 14 and both the first and second @additional gear set stages 46 and 48.

FIGURES 3,4, 5V and 6 arereproductions of theschespecically, FIG. 3 shows power-flowV forthe rst` gear gear ratio.

` FIGURE 7 isacross sectional view ofanrillus-trative o embodiment of a structure employing theV schematic showing of FIGURE l.V Like reference numerals have mission, as called for in FIGURE 1.

I-t is one of the major advantages of the split-power ,arrangementthah starting with a veryhigh input shaft rpm.. `:which is chanacteristic of a gas turbine installation,

' the desired gear reduction is' accomplished with the split- Y matic Vdrawing of FIG. l but with lthe pants shaded to ,1 show vthe actuation accomplishing the several gear ratios;

i been applied showing the principal pants of thentrans-v Y oations may be made vWithout departing from the fundamental principles and within the scope of the following Y claims:

power arrangement employing a drive connection between the input shaft andthe primaryV stage central gear,

anda second drive connection'between the primary stage ring gear and the secondary stage central gear, and a ro- Y tative connection between the secondary stage ring gear power arrangement by components of gear sets and their necessary operating elements, none of which rotate at r.p.m. of 42,600 with the Yresulting r.p.m.s of certain of the components ofthe transmission. It is particular- Y ly to be noted that -the several carriers rotate at relatively low speeds and in no case is the rotative speed of any L 5 of the pants objectionably high. Y

1st 2nd 3rd 4th Input high speed shaft 12.. 42, 600 42, 600 42, 600 42, 600 Output low speed shaft 50...- 1, 16 2,000 5, 480 6,000 VPrimary carrier 22 1, 160 2,000 1, 160 2, 000

Secondary central gearV 26 f and primary ring gear 24--. -5, 160 4, 180 5. 160 4, 180 Secondary ring gear 32- +1, 160 +960 +1, 160 +960 1st additional carrier 56- -88 Y 885 0 2nd additional carrier 70. V+1, 160 +2, OGD +1, 160 +2, 000 Primary intermediate 20. +14, 900 14, 600 14, 900 14, 600 Secondary intermediate 2S- +3, 00 +2. 420 +3, 000 +2, 420 1st additional' intermediate Y Referring tto FIGURE 2, a modified form of the invention is shown, wherein the second additional gear set'stage 48 is removed and the mechanism here shown is made up of the basic split power and primary and secondary gear sets .114'and 116. The turbine -wheel source of power 110 rotates the high speed input shaft 112 `to driwe'the cennial gear 118 intermediate gears V120', ring gear 124,V the carrier 122 making up the primary gear set vstage 114, vwhile the secondary gear set v stage has a fixed oarnier 130, central .gear 126, intermediand the output low speed shaft, the combination therewithofz` at least one' additional gear set stage in axial alignment with said input and output shaft and with said primary and secondary gear set stages,. said additional gear set stage comprising a central Vgear intermediate gears, and a ring gear;

with a carrier Vfor Vsaid intermediate gears;

a positive connection 'between said second stage cen- `tral gear andV said additional stage central gear;

and a Vpositive connection between said output low speed shaft and said additional stage ring gear; ya brake selectively actuableV to hold said addition-al gear set stage carrier from rotation or to'allow free rotation thereof;

said rotative connection comprising a one-way drive connection between said second stage ring gear and said iirst stage carrier effecting rotative connection of said second stage ring gear to said rst stage carrier and said output shaft only when drive is in direction effected when said additional gear set carrier is allowed freedom of rotation.

2. Mechanism asin claim 1 in which an outlet shaft connection Visprovided to -aiord a 'shaft rotatable concentric with saidoutput shaft and connected to rotate with said additional stage carrier, whereby a reverse speed rotation is provided by said concentric shaft when said brake allows freedom of rotation of said additional gear set stage. Y

3. Mechanism as in claim v1 in which a second additional gear set stage is provided-between tirst and second i V`sections of ,said output shaft, said additional gear set stage central gear 1512, intermediate gears 154, ring gear 1518,

and carrier 156. The central gear 126 is connected to 'the centnal gear 152 by'rthe connection 164 while the ring gear |158` is connected to the output shaft 134 through vthe connection 166. VThe brake lactuator 160, when hythereto when the gear set stage carrier 1S6'is free lto ro tate. The Oneway overnunning clutch 144 releases the connection Yof secondary ring gear d32 `from carrier 122 Y and outpfut` shaft 134 when brake 1670l is actuated. A

friction clutch-195 hydraulic or similaractuator 197 parallels the overrunning clutch 144 to .provide the couru-,ationV of the secondary ring gear 132 and the carrier 122A when the power is extracted from the reversev -outplut shafft.190.

The invention has vbeen Ydescribed by reference to the specific illustrative structure and it is intended that modicomprising:

a centnal` gear;

intermediate gears; Y Y Y and a ring gear with a carrier for intermediatev gears;

connection between said irs't additional gear set stage 'ring gear and said second additional gear set stage carrier;

said second additional gear set stage carrier also being connected `for rotation with said trst section of said output shaft; o

brake VconnectingV saidV second additional gear set stage ring gear'for selective actuation to hold said second Vadditional gear set stage ring gear from ro- `tation or to 'allow frere rotation thereof;

a one-way drive connection between said second additional gear set stage carrier and the second section of said output shaft, eiecting drive connection when rotation direction is that afforded when said second additional gear set stage brake allows free rotation of said secondtadditionalv gear set stage ring gear;

a connection between said second section of said' output shaft and said additional gear set stage central gear.

No references cited. 

1. IN COMBINATION WITH A SPLIT-POWER GEAR SET REDUCTION BETWEEN AN INPUT AND OUTPUT SHAFT OF THE TYPE EMPLOYING A PRIMARY AND A SECONDARY GEAR SET STAGE EACH WITH A CENTRAL GEAR, INTERMEDIATE GEARS, A CARRIER, AND A RING GEAR, THE PRIMARY GEAR SET CARRIER BEING PLANETARY AND ROTATING WITH THE OUTPUT SHAFT AND THE SECONDARY GEAR SET STAGE HAVING A FIXED CARRIER, SUCH TWO GEAR SET STAGE SPLITPOWER ARRANGEMENT EMPLOYING A DRIVE CONNECTION BETWEEN THE INPUT SHAFT AND THE PRIMARY STAGE CENTRAL GEAR, AND A SECOND DRIVE CONNECTION BETWEEN THE PRIMARY STAGE RING GEAR AND THE SECONDARY STAGE CENTRAL GEAR, AND A ROTATIVE CONNECTION BETWEEN THE SECONDARY STAGE RING GEAR AND THE OUTPUT LOW SPEED SHAFT, THE COMBINATION THEREWITH OF: AT LEAST ONE ADDITIONAL GEAR SET STAGE IN AXIAL ALIGNMENT WITH SAID INPUT AND OUTPUT SHAFT AND WITH SAID PRIMARY AND SECONDARY GEAR SET STAGES, SAID ADDITIONAL GEAR SET STAGE COMPRISING A CENTRAL GEAR INTERMEDIATE GEARS, AND A RING GEAR; WITH A CARRIER FOR SAID INTERMEDIATE GEARS; A POSITIVE CONNECTION BETWEEN SAID SECOND STAGE CENTRAL GEAR AND SAID ADDITIONAL STAGE CENTRAL GEAR; 